/**
 ******************************************************************************
 * @file    system_stm32f1xx.c
 * @author  MCD Application Team
 * @brief   CMSIS Cortex-M3 Device Peripheral Access Layer System Source File.
 * 
 * 1.  This file provides two functions and one global variable to be called from 
 *     user application:
 *      - SystemInit(): Setups the system clock (System clock source, PLL Multiplier
 *                      factors, AHB/APBx prescalers and Flash settings). 
 *                      This function is called at startup just after reset and 
 *                      before branch to main program. This call is made inside
 *                      the "startup_stm32f1xx_xx.s" file.
 *
 *      - SystemCoreClock variable: Contains the core clock (HCLK), it can be used
 *                                  by the user application to setup the SysTick 
 *                                  timer or configure other parameters.
 *                                     
 *      - SystemCoreClockUpdate(): Updates the variable SystemCoreClock and must
 *                                 be called whenever the core clock is changed
 *                                 during program execution.
 *
 * 2. After each device reset the HSI (8 MHz) is used as system clock source.
 *    Then SystemInit() function is called, in "startup_stm32f1xx_xx.s" file, to
 *    configure the system clock before to branch to main program.
 *
 * 4. The default value of HSE crystal is set to 8 MHz (or 25 MHz, depending on
 *    the product used), refer to "HSE_VALUE". 
 *    When HSE is used as system clock source, directly or through PLL, and you
 *    are using different crystal you have to adapt the HSE value to your own
 *    configuration.
 *        
 ******************************************************************************
 * @attention
 *
 * <h2><center>&copy; Copyright (c) 2017 STMicroelectronics.
 * All rights reserved.</center></h2>
 *
 * This software component is licensed by ST under BSD 3-Clause license,
 * the "License"; You may not use this file except in compliance with the
 * License. You may obtain a copy of the License at:
 *                        opensource.org/licenses/BSD-3-Clause
 *
 ******************************************************************************
 */

/** @addtogroup CMSIS
 * @{
 */

/** @addtogroup stm32f1xx_system
 * @{
 */

/** @addtogroup STM32F1xx_System_Private_Includes
 * @{
 */

#include "stm32f1xx.h"

/**
 * @}
 */

/** @addtogroup STM32F1xx_System_Private_TypesDefinitions
 * @{
 */

/**
 * @}
 */

/** @addtogroup STM32F1xx_System_Private_Defines
 * @{
 */

#if !defined  (HSE_VALUE) 
  #define HSE_VALUE               8000000U /*!< Default value of the External oscillator in Hz.
                                                This value can be provided and adapted by the user application. */
#endif /* HSE_VALUE */

#if !defined  (HSI_VALUE)
  #define HSI_VALUE               8000000U /*!< Default value of the Internal oscillator in Hz.
                                                This value can be provided and adapted by the user application. */
#endif /* HSI_VALUE */

/*!< Uncomment the following line if you need to use external SRAM  */
#if defined(STM32F100xE) || defined(STM32F101xE) || defined(STM32F101xG) || defined(STM32F103xE) || defined(STM32F103xG)
/* #define DATA_IN_ExtSRAM */
#endif /* STM32F100xE || STM32F101xE || STM32F101xG || STM32F103xE || STM32F103xG */

/*!< Uncomment the following line if you need to relocate your vector Table in
 Internal SRAM. */
/* #define VECT_TAB_SRAM */
#define VECT_TAB_OFFSET  0x00000000U /*!< Vector Table base offset field. 
                                  This value must be a multiple of 0x200. */

/**
 * @}
 */

/** @addtogroup STM32F1xx_System_Private_Macros
 * @{
 */

/**
 * @}
 */

/** @addtogroup STM32F1xx_System_Private_Variables
 * @{
 */

/* This variable is updated in three ways:
 1) by calling CMSIS function SystemCoreClockUpdate()
 2) by calling HAL API function HAL_RCC_GetHCLKFreq()
 3) each time HAL_RCC_ClockConfig() is called to configure the system clock frequency 
 Note: If you use this function to configure the system clock; then there
 is no need to call the 2 first functions listed above, since SystemCoreClock
 variable is updated automatically.
 */
uint32_t SystemCoreClock = 16000000;
const uint8_t AHBPrescTable[16U] = { 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 6, 7,
		8, 9 };
const uint8_t APBPrescTable[8U] = { 0, 0, 0, 0, 1, 2, 3, 4 };

/**
 * @}
 */

/** @addtogroup STM32F1xx_System_Private_FunctionPrototypes
 * @{
 */

#if defined(STM32F100xE) || defined(STM32F101xE) || defined(STM32F101xG) || defined(STM32F103xE) || defined(STM32F103xG)
#ifdef DATA_IN_ExtSRAM
  static void SystemInit_ExtMemCtl(void); 
#endif /* DATA_IN_ExtSRAM */
#endif /* STM32F100xE || STM32F101xE || STM32F101xG || STM32F103xE || STM32F103xG */

/**
 * @}
 */

/** @addtogroup STM32F1xx_System_Private_Functions
 * @{
 */

/**
 * @brief  Setup the microcontroller system
 *         Initialize the Embedded Flash Interface, the PLL and update the 
 *         SystemCoreClock variable.
 * @note   This function should be used only after reset.
 * @param  None
 * @retval None
 */
void SystemInit(void)
{
	/* Reset the RCC clock configuration to the default reset state(for debug purpose) */
	/* Set HSION bit */
	RCC->CR |= 0x00000001U;

	/* Reset SW, HPRE, PPRE1, PPRE2, ADCPRE and MCO bits */
#if !defined(STM32F105xC) && !defined(STM32F107xC)
	RCC->CFGR &= 0xF8FF0000U;
#else
	RCC->CFGR &= 0xF0FF0000U;
#endif /* STM32F105xC */   

	/* Reset HSEON, CSSON and PLLON bits */
	RCC->CR &= 0xFEF6FFFFU;

	/* Reset HSEBYP bit */
	RCC->CR &= 0xFFFBFFFFU;

	/* Reset PLLSRC, PLLXTPRE, PLLMUL and USBPRE/OTGFSPRE bits */
	RCC->CFGR &= 0xFF80FFFFU;

#if defined(STM32F105xC) || defined(STM32F107xC)
	/* Reset PLL2ON and PLL3ON bits */
	RCC->CR &= 0xEBFFFFFFU;

	/* Disable all interrupts and clear pending bits  */
	RCC->CIR = 0x00FF0000U;

	/* Reset CFGR2 register */
	RCC->CFGR2 = 0x00000000U;
#elif defined(STM32F100xB) || defined(STM32F100xE)
	/* Disable all interrupts and clear pending bits  */
	RCC->CIR = 0x009F0000U;

	/* Reset CFGR2 register */
	RCC->CFGR2 = 0x00000000U;
#else
	/* Disable all interrupts and clear pending bits  */
	RCC->CIR = 0x009F0000U;
#endif /* STM32F105xC */

#if defined(STM32F100xE) || defined(STM32F101xE) || defined(STM32F101xG) || defined(STM32F103xE) || defined(STM32F103xG)
  #ifdef DATA_IN_ExtSRAM
    SystemInit_ExtMemCtl(); 
  #endif /* DATA_IN_ExtSRAM */
#endif 

#ifdef VECT_TAB_SRAM
  SCB->VTOR = SRAM_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal SRAM. */
#else
	SCB->VTOR = FLASH_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal FLASH. */
#endif 
}

/**
 * @brief  Update SystemCoreClock variable according to Clock Register Values.
 *         The SystemCoreClock variable contains the core clock (HCLK), it can
 *         be used by the user application to setup the SysTick timer or configure
 *         other parameters.
 *           
 * @note   Each time the core clock (HCLK) changes, this function must be called
 *         to update SystemCoreClock variable value. Otherwise, any configuration
 *         based on this variable will be incorrect.         
 *     
 * @note   - The system frequency computed by this function is not the real 
 *           frequency in the chip. It is calculated based on the predefined 
 *           constant and the selected clock source:
 *             
 *           - If SYSCLK source is HSI, SystemCoreClock will contain the HSI_VALUE(*)
 *                                              
 *           - If SYSCLK source is HSE, SystemCoreClock will contain the HSE_VALUE(**)
 *                          
 *           - If SYSCLK source is PLL, SystemCoreClock will contain the HSE_VALUE(**) 
 *             or HSI_VALUE(*) multiplied by the PLL factors.
 *         
 *         (*) HSI_VALUE is a constant defined in stm32f1xx.h file (default value
 *             8 MHz) but the real value may vary depending on the variations
 *             in voltage and temperature.   
 *    
 *         (**) HSE_VALUE is a constant defined in stm32f1xx.h file (default value
 *              8 MHz or 25 MHz, depending on the product used), user has to ensure
 *              that HSE_VALUE is same as the real frequency of the crystal used.
 *              Otherwise, this function may have wrong result.
 *                
 *         - The result of this function could be not correct when using fractional
 *           value for HSE crystal.
 * @param  None
 * @retval None
 */
void SystemCoreClockUpdate(void)
{
	uint32_t tmp = 0U, pllmull = 0U, pllsource = 0U;

#if defined(STM32F105xC) || defined(STM32F107xC)
  uint32_t prediv1source = 0U, prediv1factor = 0U, prediv2factor = 0U, pll2mull = 0U;
#endif /* STM32F105xC */

#if defined(STM32F100xB) || defined(STM32F100xE)
  uint32_t prediv1factor = 0U;
#endif /* STM32F100xB or STM32F100xE */

	/* Get SYSCLK source -------------------------------------------------------*/
	tmp = RCC->CFGR & RCC_CFGR_SWS;

	switch (tmp) {
	case 0x00U: /* HSI used as system clock */
		SystemCoreClock = HSI_VALUE;
		break;
	case 0x04U: /* HSE used as system clock */
		SystemCoreClock = HSE_VALUE;
		break;
	case 0x08U: /* PLL used as system clock */

		/* Get PLL clock source and multiplication factor ----------------------*/
		pllmull = RCC->CFGR & RCC_CFGR_PLLMULL;
		pllsource = RCC->CFGR & RCC_CFGR_PLLSRC;

#if !defined(STM32F105xC) && !defined(STM32F107xC)      
		pllmull = (pllmull >> 18U) + 2U;

		if (pllsource == 0x00U) {
			/* HSI oscillator clock divided by 2 selected as PLL clock entry */
			SystemCoreClock = (HSI_VALUE >> 1U) * pllmull;
		} else {
#if defined(STM32F100xB) || defined(STM32F100xE)
       prediv1factor = (RCC->CFGR2 & RCC_CFGR2_PREDIV1) + 1U;
       /* HSE oscillator clock selected as PREDIV1 clock entry */
       SystemCoreClock = (HSE_VALUE / prediv1factor) * pllmull; 
 #else
			/* HSE selected as PLL clock entry */
			if ((RCC->CFGR & RCC_CFGR_PLLXTPRE) != (uint32_t) RESET) {/* HSE oscillator clock divided by 2 */
				SystemCoreClock = (HSE_VALUE >> 1U) * pllmull;
			} else {
				SystemCoreClock = HSE_VALUE * pllmull;
			}
#endif
		}
#else
      pllmull = pllmull >> 18U;
      
      if (pllmull != 0x0DU)
      {
         pllmull += 2U;
      }
      else
      { /* PLL multiplication factor = PLL input clock * 6.5 */
        pllmull = 13U / 2U; 
      }
            
      if (pllsource == 0x00U)
      {
        /* HSI oscillator clock divided by 2 selected as PLL clock entry */
        SystemCoreClock = (HSI_VALUE >> 1U) * pllmull;
      }
      else
      {/* PREDIV1 selected as PLL clock entry */
        
        /* Get PREDIV1 clock source and division factor */
        prediv1source = RCC->CFGR2 & RCC_CFGR2_PREDIV1SRC;
        prediv1factor = (RCC->CFGR2 & RCC_CFGR2_PREDIV1) + 1U;
        
        if (prediv1source == 0U)
        { 
          /* HSE oscillator clock selected as PREDIV1 clock entry */
          SystemCoreClock = (HSE_VALUE / prediv1factor) * pllmull;          
        }
        else
        {/* PLL2 clock selected as PREDIV1 clock entry */
          
          /* Get PREDIV2 division factor and PLL2 multiplication factor */
          prediv2factor = ((RCC->CFGR2 & RCC_CFGR2_PREDIV2) >> 4U) + 1U;
          pll2mull = ((RCC->CFGR2 & RCC_CFGR2_PLL2MUL) >> 8U) + 2U; 
          SystemCoreClock = (((HSE_VALUE / prediv2factor) * pll2mull) / prediv1factor) * pllmull;                         
        }
      }
#endif /* STM32F105xC */ 
		break;

	default:
		SystemCoreClock = HSI_VALUE;
		break;
	}

	/* Compute HCLK clock frequency ----------------*/
	/* Get HCLK prescaler */
	tmp = AHBPrescTable[((RCC->CFGR & RCC_CFGR_HPRE) >> 4U)];
	/* HCLK clock frequency */
	SystemCoreClock >>= tmp;
}

#if defined(STM32F100xE) || defined(STM32F101xE) || defined(STM32F101xG) || defined(STM32F103xE) || defined(STM32F103xG)
/**
  * @brief  Setup the external memory controller. Called in startup_stm32f1xx.s 
  *          before jump to __main
  * @param  None
  * @retval None
  */ 
#ifdef DATA_IN_ExtSRAM
/**
  * @brief  Setup the external memory controller. 
  *         Called in startup_stm32f1xx_xx.s/.c before jump to main.
  *         This function configures the external SRAM mounted on STM3210E-EVAL
  *         board (STM32 High density devices). This SRAM will be used as program
  *         data memory (including heap and stack).
  * @param  None
  * @retval None
  */ 
void SystemInit_ExtMemCtl(void) 
{
  __IO uint32_t tmpreg;
  /*!< FSMC Bank1 NOR/SRAM3 is used for the STM3210E-EVAL, if another Bank is 
    required, then adjust the Register Addresses */

  /* Enable FSMC clock */
  RCC->AHBENR = 0x00000114U;

  /* Delay after an RCC peripheral clock enabling */
  tmpreg = READ_BIT(RCC->AHBENR, RCC_AHBENR_FSMCEN);
  
  /* Enable GPIOD, GPIOE, GPIOF and GPIOG clocks */
  RCC->APB2ENR = 0x000001E0U;
  
  /* Delay after an RCC peripheral clock enabling */
  tmpreg = READ_BIT(RCC->APB2ENR, RCC_APB2ENR_IOPDEN);

  (void)(tmpreg);
  
/* ---------------  SRAM Data lines, NOE and NWE configuration ---------------*/
/*----------------  SRAM Address lines configuration -------------------------*/
/*----------------  NOE and NWE configuration --------------------------------*/  
/*----------------  NE3 configuration ----------------------------------------*/
/*----------------  NBL0, NBL1 configuration ---------------------------------*/
  
  GPIOD->CRL = 0x44BB44BBU;  
  GPIOD->CRH = 0xBBBBBBBBU;

  GPIOE->CRL = 0xB44444BBU;  
  GPIOE->CRH = 0xBBBBBBBBU;

  GPIOF->CRL = 0x44BBBBBBU;  
  GPIOF->CRH = 0xBBBB4444U;

  GPIOG->CRL = 0x44BBBBBBU;  
  GPIOG->CRH = 0x444B4B44U;
   
/*----------------  FSMC Configuration ---------------------------------------*/  
/*----------------  Enable FSMC Bank1_SRAM Bank ------------------------------*/
  
  FSMC_Bank1->BTCR[4U] = 0x00001091U;
  FSMC_Bank1->BTCR[5U] = 0x00110212U;
}
#endif /* DATA_IN_ExtSRAM */
#endif /* STM32F100xE || STM32F101xE || STM32F101xG || STM32F103xE || STM32F103xG */

/**
 * @}
 */

/**
 * @}
 */

/**
 * @}
 */
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
